A PVDF-HFP-Based\nGel Polymer Electrolyte onto Air Cathode by UV-Curing for Lithium–Oxygen\nBatteries

Using gel polymer electrolytes (GPEs) instead of liquid\nelectrolytes is a sensible and effective strategy for safety reasons.\nA GPE membrane was prepared by UV-curing using poly(vinylidene fluoride-<i>co</i>-hexafluoropropylene) (PVDF-HFP) as the polymer substrate\nmaterial and an optimized ratio. The GPE membrane exhibited good flexibility\nand a higher ionic conductivity (σ = 0.63 mS cm<sup>–1</sup>). The RuO<sub>2</sub>@C/GPE/Li (abbreviated as S-GPE) battery is\nemployed to demonstrate the electrochemical performance of GPE. The\nbattery exhibits an <i>R</i><sub>ct</sub> of 255.9 Ω,\naccompanied by a lack of cycle stability, with a cycle life of only\n110 h. The results indicate that it is challenging to enhance the\nbattery’s overall performance by solely improving the internal\ntransfer performance of the electrolyte and ignoring the high interface\nimpedance caused by the “solid–solid” contact\nat the electrolyte–electrode interface. Based on these findings,\na straightforward one-step method is adopted to combine GPE with the\nair cathode by <i>in situ</i> photopolymerization and assemble\nit into RuO<sub>2</sub>@C-GPE/Li (abbreviated as I-GPE) battery used\nto demonstrate the electrochemical performance of the integrated GPE.\nThe <i>R</i><sub>ct</sub> value of the battery is 89.66\nΩ, with a notable improvement in cycle stability. The battery’s\ncycle life is 940 h, which is 8.5 times that of the sandwich structure\nlithium–oxygen battery. The results indicate that preparing\nan integrated GPE by <i>in situ</i> photopolymerization\nof the electrolyte electrode is a straightforward and effective method\nto improve poor interfacial compatibility and can provide a theoretical\nbasis for subsequent in-depth research.